Electron discharge device with electrode spacer having integral electron vibration dampening member thereon

ABSTRACT

An insulative electrode spacer member is provided for an electron discharge device, which spacer comprises a disc of natural mica provided with a cathode dampening arm as an integral part of the spacer. A hole is formed in the mica spacer adjacent the dampening arm for the insertion of a cathode which is properly engaged by a free end of the dampening arm which is positioned on the top of the cathode. The cathode may be notched at the top and the arm so positioned with respect thereto that the arm only engages the bottom of the notch when the cathode expands due to normal operational heating.

United States Patent William F. Cullen [72] Inventors Philpot, Ky.;Othrnar E. Ringeman, St. Meinrad, Ind. [2]] Appl. No. 783,543 [22] FiledDec. 13, 1968 [45] Patented May 18, 1971 [73] Assignee General ElectricCompany [54] ELECTRON DISCHARGE DEVICE WITH ELECTRODE SPACER HAVINGINTEGRAL ELECTRON VIBRATION DAMPENING MEMBER THEREON 4 Claims, 5 DrawingFigs.

[52] US. Cl 313/269, 313/250, 313/257, 313/289 [5i] Int. Cl H013 1/18,H01 j 19/12 [50] Field of Search 313/289, 269, 257, 256, 250

[56] References Cited UNITED STATES PATENTS 2,494,853 1/l950 Alma313/269X FOREIGN PATENTS 246,656 5/1963 Australia 313/169 258,368 5/1963Australia 313/169 Primary Examiner-John W. Huckert AssistantExaminer-Andrew J. James AttorneysNathan J. Cornfeld, John P. Taylor,Frank L.

Neuhauser and Oscar B. Waddell ABSTRACT: An insulative electrode spacermember is provided for an electron discharge device, which spacercomprises a disc of natural mica provided with a cathode dampening armas an integral part of the spacer. A hole is formed in the mica spaceradjacent the dampening arm for the insertion of a cathode which isproperly engaged by a free end of the dampening arm which is positionedon the top of the cathode. The cathode may be notched at the top and theam so positioned with respect thereto that the am only engages thebottom of the notch when the cathode expands due to normal operationalheating.

Patented May 18, 1971 3,579,020

F|G.2. Fl (5.3.

mks:

1c I2 mm IN V ENTORS:

WILLIAM F. CULLEN OTHMAR E. RINGEMAN,

THEIR ATTORNEY.

ELECTRON, DISCHARGE DEVICE WITH ELECTRODE SPACER HAVING INTEGRALELECTRON VIBRATION DAMPENING MEMBER THEREON IMPROVED ELECTRON DISCHARGEDEVICE HAVING IMPROVED ELECTRODE SPACER BACKGROUND or THE INVENTION Thisinvention relates to electron discharge devices and more particularly toan electrode and electrode spacer arrangement whereby the electrodespacer is provided with a cathode-dampening arm used to precludemicrophonics due to cathode vibration.

It has been found that one of the most common causes of v microphonicsin electron discharge devices is the excessive vibrative movement of acathode mounted within a surrounding insulative spacer member, such as amica disc. Currently used cathodes are somewhat more sophisticated andfragile than earlier cathodes and, consequently, the problem of cathodemovement and dampening has become somewhat aggravated by this fragilenature. If a cathode is secured too tightly by a spacer, it has apropensity to either deform when heated (resulting in interelementshorts or shifts in the electrical characteristics of the electrondischarge device) or to even collapse due to excessive moments appliedabout the base of the cathode mounting. Another problem encountered inmounting a cathode within an electron discharge device is an excessiveheat drain from the cathode due to a very tight cathode-to-mica fit,which heat drain results in unsatisfactory electron dischargeperformance at reduced heater voltages.

It has been proposed to check excessive movement or vibration of thecathode by the addition of a second mica member anchored to theconventional mica spacer disc, which second member has a flexible armfor resting or pressing against the side of the cathode so as to dampcathode movement in an attempt to preclude microphonics.

This configuration of electron discharge spacer has worked with somesuccess in reducing cathode microphonics, but it does have severalweighty disadvantages in that it is quite costly and requires anadditional mica member as well as addi- 1 tional intricate steps in theconstruction thereof. Likewise, the use of arms or tabs pressing on theside of a cathode in an electron discharge device does tend to deformmany of the more fragile cathodes currently in use. During the heatingand cooling of a cathode, considerable expansion and contraction resultswhich, in turn, causes continual bending and deflection of the mica arm.Since natural mica, the preferred material used for electrode spacerdiscs, is brittle and since the fatigue limit of such a brittle materialis rather low, it is quite possible for the mica cathode-dampening armto break. Since the cathode is mounted with the effect of the momentresulting from the mica arm pressing against the side of the cathodetaken into account for proper cathode placement purposes, if the micaarm is subsequently broken, the cathode within has a tendency to bendtoward the arm and become misaligned from the proper position occupiedbefore the break.

OBJECTS OF THE INVENTION Accordingly, one object of the presentinvention is to provide a spacer member and electrode arrangement for anelectron discharge device which is of simple configuration, economicaland easy to install.

Another object of the present invention is to provide a spacer memberfor an electron discharge device which will not deflect or apply anormal force to a cathode which is to be dampened in an effort topreclude microphonics.

It is still a further object of this invention to provide a spacermember for an electron discharge device which will not cause a cathodeto misalign if it should be broken by shock or vibration forces.

SUMMARY OF THE INVENTION In carrying out the invention in a preferredform, a spacer member is provided for use in an electron dischargedevice which spacer includes a flexible arm resiliently flexed andpositioned on top of a cathode projecting through an opening defined inthe spacer member.

The subject matter which is regarded as the invention is particularlypointed out and distinctly claimed in a concluding portion of thisspecification. The invention, however, both as to organization andmethod of practice, together with further objects and advantagesthereof, may best be understood by a reference to the followingdescription of the preferred embodiment taken in connection with theaccompanying drawings in which:

FIG. 1 is an isometric view of the improved spacer member and electrodearrangement of the invention.

FIG. 2 is a section view taken along the line IIII shown'in FIG. 1.

FIG. 3 is a cross-sectional view of a preferred embodiment of theinvention shown with the cathode in a cold condition.

FIG. 4 is a cross-sectional view of the embodiment of FIG. 3 showing thecathode in a heated condition.

FIG. 5 is a fragmentary top view of another embodiment of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings onwhich like numbers are used to indicate like parts throughout thevarious views thereof, FIGS. 1 and 2 show an improved spacer member 10comprising two semicircular mica discs 14 and 16. Disc 14 is integrallyformed witha cathode-dampening arm 12 projecting over a portion of disc16. An opening 18 is defined within spacer l6 and is sized to allow theprojection of a cathode 20 therethrough. It will be noted that in theillustrated embodiment the cathode is not centrally located with respectto the axis defined by the two semicircular spacers. This allowscathode-dampening arm 12 to be of relatively long length with respect tothe diameter defined by the two semicircular discs without terminatingat a point so close to the edge of disc 14 to structurally weaken thedisc. This relatively long length allows arm 12 to properly flex uponthermal expansion of the cathode upon heating.

It should be noted that the cathode-dampening arm 12 of the invention ispositioned to apply a force parallel and not normal to the vertical axisof the cathode and, as such, if the dampening arm 12 should break, thecathode would not tend to misalign. Likewise, the force of the arm 12against the cathode will not distort or deflect the cathode upon heatingas the arm is not applying a force in an unsupported direction normal tothe axis of the cathode.

One problem which may be encountered in the embodiment shown in FIGS. 1and 2 is that of fatigue failure of the dampening arm 12 due to cyclicor intermittent heating and cooling of the cathode 20. If this shouldprove to be a problem in operation, the cathode may be configured with anotch 22 formed in the top thereof, as shown in FIG. 3. With thisarrangement, cathode 20' contacts the arm 12 only when the cathode hasexpanded due to operational heating. Consequently, arm 12 is notsubjected to severe deflections and fatigue failure of arm 12 isprecluded. FIG. 4 shows cathode 20' heated and ex panded to meetdampening arm 12 as per the above discussion. It should be noted inFIGS. 3 and 4 that notch 22 in cathode 20' is tapered so that dampeningarm 12 only makes point contacts (or line contacts) on either side ofthe notch so as to avoid excessive heat drain from the cathode throughthe mica dampening arm 12.

FIG. 5 shows another embodiment of the invention whereby the end ofdampening arm 12 which contacts cathode 20 is itself formed with a notch24 so that the arm engages cathode 20 only at two point contacts 26 and28. In this embodiment, excessive heat drain is also minimized by theminimum contact area between cathode 20 and dampening arm 12. However,in this embodiment, vertical access to the cathode from above is alsopermitted by the shape of the dampening arm 12. This has been found tobe beneficial particularly when utilizing the invention with indirectlyheated cathodes.

in accordance with the invention dampening arm 12 is formed integrallywith the mica spacer disc. While the embodiment illustrated in FIG. 1uses a two-piece spacer when the cathode is mounted in an offsetposition which is the preferred arrangement for use, for example, inmultifunction tubes or the like, it is to be understood that theinvention also contemplates the use of a unitary spacer disc with acentrally positioned cathode, particularly in larger tubes whereformation of the arm integrally from a unitary mica spacer would notunduly weaken the spacer due to the larger diameter of the tube andcorresponding spacer.

The embodiment shown in F108. 3 and 4 shows a notched cathode embodimentin which arm 12 is preconditioned so as to be disposed above the notchof the cathode in its relaxed state. Only when the cathode is heated andis thereby caused to expand does it contact dampening arm 12 and thenthe engagement is only at two point contacts. This arrangement therebyprecludes failure of the dampening arm due to severe deflection traveland checks excessive dissipation of heat from the cathode to the arm.The notched dampening arm shown in FIG. is the reverse embodiment of thenotched cathode and provides the same advantage of lessened heatdissipation by minimizing cathode/mica contact.

While the preferred embodiment of the applicants invention has beenshown in the simplest form, it is of course understood that variousmodifications may be made therein without departing from the spirit andscope thereof, and it is therefore intended to cover in the claimsappended hereto all such variations as fall within the true spirit andscope of the present invention.

We claim:

1. An improved electron discharge device comprising an electrode spacersaid spacer having an opening defined therein and an electrodeprojecting therethrough, said spacer having a flexible arm integrallyformed thereon and preconditioned to be disposed above and in contactwith the top of said electrode said flexible arm being so positionedwith respect to said electrode that when said electrode is operationallyheated, said electrode expands and exert a pressure on said flexiblearm, whereby said arm is caused to apply a force which is substantiallysolely parallel to the vertical axis of the electrode whereby movementof the electrode is dampened.

2. An improved electron discharge device including an electrode spacer,a cathode projecting through said spacer, an electrode dampening armforming an integral part of said spacer, said cathode being formed witha tapered notch in the top thereof, said flexible arm preconditioned tobe disposed above said notch when the cathode is in a cold condition,said flexible arm so positioned and said tapered notch so formed thatwhen said cathode is operationally heated said cathode expands to engagesaid flexible arm at either side of said notch to apply a force paralleland not normal to the-vertical axis of the electrode.

3. The spacer as defined in claim 1 wherein said spacer comprises mica.

4. The spacer as defined in claim 2 wherein said spacer comprises mica.

1. An improved electron discharge device comprising an electrode spacer said spacer having an opening defined therein and an electrode projecting therethrough, said spacer having a flexible arm integrally formed thereon and preconditioned to be disposed above and in contact with the top of said electrode said flexible arm being so positioned with respect to said electrode that when said electrode is operationally heated, said electrode expands and exert a pressure on said flexible arm, whereby said arm is caused to apply a force which is substantially solely parallel to the vertical axis of the electrode whereby movement of the electrode is dampened.
 2. An improved electron discharge device including an electrode spacer, a cathode projecting through said spacer, an electrode dampening arm forming an integral part of said spacer, said cathode being formed with a tapered notch in the top thereof, said flexible arm preconditioned to be disposed above said notch when the cathode is in a cold condition, said flexible arm so positioned and said tapered notch so formed that when said cathode is operationally heated said cathode expands to engage said flexible arm at either side of said notch to apply a force Parallel and not normal to the vertical axis of the electrode.
 3. The spacer as defined in claim 1 wherein said spacer comprises mica.
 4. The spacer as defined in claim 2 wherein said spacer comprises mica. 